Columnar rack printer with ribbon shift alternator



p 1964 D. J. SMlTHBAUER COLUMNAR RACK PRINTER WITH RIBBON SHIFTALTERNATOR 3 Sheets-Sheet 1 Filed Oct. 22, 1962 EQU N IN VENTOR. DONALDJ. sun/mum.

A T TORNE X COLUMNAR RACK PRINTER WITH RIBBON SHIFT ALTERNATOR FiledOct. 22, 1962 Sept. 8, 1964 D. J. SMITHBAUER 3 Sheets-Sheet 2 INVENTOR.00mm J SMITHBAl/ER.

ATTORNEY Sept. 8, 1964 D. J. SMITHBAUER 3,147,703

COLUMNAR RACK PRINTER WITH RIBBON SHIFT ALTERNATOR Filed Oct. 22, 1962 3Sheets-Sheet 5 (\I N u:

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.of the ribbon lift spindles. "part of a cyclically operable ribbonadvancing mechanism United States Patent 3,147,703 CQLUMNAR RACK PRINTERWITH RIBBON SIEHET ALTERNATQR Donald J. Smithbauer, Detroit, Mich,assignor to Barroughs (Iorporation, Detroit, Mich, a corporation ofMichigw Filed Get. 22, 1962, Ser. No. 232,199 7 Claims. (6!. 101 336)This invention relates to ink ribbon printing devices, and, moreparticularly, to ribbon field selection apparatus for ribbon liftingmechanisms.

The invention seeks generally to improve the uniformity of printingdensity across an entire printing line and to prolong the serviceabilityof inked ribbons from the standpoint of ribbon wear and life in printingdevices using an inked ribbon.

Towards the accomplishment of these aims and objects, the inventionprovides an alternator for a ribbon shift mechanism that automaticallyalternates the shift or lift of the ribbon to the upper half and to thelower half thereof on successive printing cycles or operations of aprinting device.

For an appreciation of the manner in which the above and other objectsof the invention are attained, reference is made to the followingdescription and attending drawings, in which:

FIG. 1 is an exploded, isometric view, with parts broken away, of a partof a printing apparatus embodying the essential elements of the ribbonshift alternator mechanism of the present invention;

FIG. 2 is a side elevation view taken from the right of FIG. 1;

FIGS. 3 and 4- are views illustrating different positions of the subjectalternator mechanism to explain the operation of the invention, and

FIG. 5 is a top plan View showing the relative lateral spacings of theparts of the subject alternator mechanism.

Referring to the drawings, FIG. 1 illustrates an improved ribbon liftand control mechanism for a full line, word printer of the typedescribed more fully in copending US. application S.N. 17,200, filedMarch 23, 1960, for

William W. Deighton, of common ownership herewith,

the side frames is a pair of supporting guide brackets 14,

15 for a pair of ribbon lift spindles 16, 17. Each spindle mounts aribbon spool 19, 20 carrying an ink ribbon 21 extending therebetween andof such width relative to the printing type faces of the printer as toprovide two printing field corresponding to the upper half 21U and tothe .lower half 21L of the ribbon. Mounted rearwardly of the ribbon is aplaten 22 having a print receiving record medium 23, such as a ledgercard, journal roll or tape, rolled Iournalled in and extending throughthe side frames is a rotatable ribbon lift shaft 24 having fixed to eachend thereof a rearwardly extending lift arm 25, 26, each having aslotted end attached by an adjustable stud and nut 27, to theintermediate portion of a respective one Also shown in FIG. 1 is a 28,which is similar to that employed in T. M. Butler Patent No. 2,629,549and operates in conjunction with the ribbon shift alternator mechanismherein although forming no part thereof.

Near the inside of the right side frame 13, a dual arm and cam followerassembly, comprised of a short arm 30 and a long, cam follower arm 31 isprovided on the ribbon lift shaft 24. The short arm 30 is pinned to theshaft through a hub portion secured to the upper end thereof and isforwardly tensioned by spring 33 secured to a stud on the right sideframe, thereby urging the ribbon spindles to limit downwardly on theirmounting brackets and positioning the ribbon in an inactive positionbelow the printing line indicated by the dashed and dotted line on therecord medium 23 in FIG. 1. The longer arm 31 is pivotally mountedthrough its center on a stud 34 secured to and passing through the lowerend of the shorter arm and includes an elongated opening 35, shown inFIGS. 2, 3 and 4, in its upper end through which passes the lift shaft24. The lower end of the arm 31 carries a cam follower roller 37 and isforwardly biased by spring 38 to tension the roller to the cam surfaceof a cam 40 secured to and carried on the cam drive shaft 39 of theprinting device. The drive shaft is journalled in and extends throughthe side frames and is belt driven from a continuously running motor(not shown) through a onerevolution clutch 41, the tripping of whichinitiates a printing cycle.

In order that a print take place on the upper half or field of theribbon, the lift arms receive the lesser of two possible elevating orvertical lift motions. During an upper ribbon field print cycle, the cam40 attached to the main cam shaft 39 causes the follower arm 31 to pivotabout stud 34 in a counterclockwise direction, as viewed from the rightside of the printer device as in FIG. 2, without imparting motion to thestud, until such time as the right or rearwardly disposed end wall ofthe elongated slot 35 limits against the ribbon lift shaft 24. Upon afurther camming of the follower arm 31, it no longer pivots on stud 34,but transfers its counterclockwise motion through the stud to the shortarm 30, which, being pinned to the lift shaft, rotates the shaftcounterclockwise to swing the lift arms 25, 26 upwardly and lift theribbon from an inactive position, 1, below the print line to a firstraised position, R1, where the upper ribbon field 21U is in line withthe active type, the inactive and raised ribbo positions being indicatedin FIG. 2.

In order to provide a greater lift to the ribbon so that the lower halfor ribbon field 21L thereof will be presented to the printing line,there is provided an interposer 43 in the form of a bail that ispivotally mounted on a stud 44 secured to and extending inwardly fromthe right side frame 13. The interposer includes an extended tab portion46, which in FIGS. 2 and 3 is shown out of the path of a stepped notchor cut-out portion 47 provided on the upper end of the cam follower arm31. By displacing the interposer tab downwardly to engage the shoulderedcutout portion of the follower arm, the follower arm is prevented fromshifting as much in the slot 35 and the interposer tab 46 acts as alimit stop or fulcrum for the follower arm. Since there is not as muchlost motion of the follower arm on the lift shaft than in the previouslydescribed upper ribbon field printing cycle or operation, a greatermotion is transferred to the shorter arm 30 and to the lift shaft with aconsequent greater lift of the ribbon spindles to a higher elevation orsecond raised position, R2, where the lower half 21L or field of theribbon will be aligned with the line of active printing type.

In accordance with the present invention, the interposer isautomatically rocked into and out of the path of the follower arm 31 onsuccessive printing cycles or operations by an alternator mechanism 56which causes the upper half and lower half of the advancing ribbon to bealternately presented to the print line in order to provide uniformprinting density thereacross and to prolong the service life anddecrease the wear of a monochrome ribbon. The ribbon lift alternator isa bistable type reversing device, which in the illustrated form of theinvention, is a mechanically actuated spring toggle mechanism comprisinga rocker element 51, a cyclically operable driver arm 52 and anover-center compression spring 53.

As defined by the dictionary and common usage, the terms alternate andsuccessive both mean one following the other. Also, the dictionarydefinition of the term alternate includes the meaning of successive.Accordingly, as used herein, alternate connotes change of position;whereas, successive connotes a time relationship.

The rocker element is a semi-circular disc having a pair of contiguous,upper and lower scallop-shaped camming surfaces 55, 56 formed thereinand located above and below its central mounting on a stud 57. Stud 57extends inwardly from and its mounted on the right side frame 13 andcarries a bracket 58 fixed thereon for guiding the toggle spring 53 ofthe alternator mechanism. The intersection of the cut-out cammingportions 55, 56 of the rocker element forms a rearwardly directed,centrally located peaked or nose portion 59, the tip of which is on aline passing through the pivot center of the rocker element. Integrallyformed on the forwardly facing diametrical edge or surface of the rockerelement is a downwardly canted protuberance 60 for receiving one end ofthe compression spring 53 thereon.

The driver arm 52 has a forwardly pointed end, which is adapted toengage and to be positioned in either of the camming surfaces of therocker element, and is connected at its other end by a centering spring61 to a rod or stud 62 carried on an end bracket arm 63 secured to theexisting hammer latch bail 64 of the printing device shown in theaforementioned Deighton application.

Extending forwardly of the laterally extending hammer latch bail andconnected to the aforesaid rod 62 on the end bracket 63 thereof is adrive link 65 which is pivotally connected near its forward end to theupper end of a cam follower rocker arm 66 that is pivotally mountedintermediate its ends to the lift shaft 24. The lower end of the rockerarm 66 carries a roller 67 and is forwardly tensioned by a spring 68against another cam 69 carried on the main cam shaft 59. The driver arm52 is coupled to the drive link 65, which drives the hammer latchingbail, through a broken joint connection which includes a rod 70 slidablymounted in and extending through an elongated slot 71 in the drive link.A drive spring 72 for the broken joint is connected at one end to aninwardly extending stud 73 on the forward end of the drive link, theother end of the spring being connected to one end of the rod 70 therebyurging the rod 70 against the forwardly disposed wall of the slotprovided in the link. The rod 76 provides a pivot mounting for the drivearm 52 through a centrally located hub 54 provided on the latter member.

The toggle spring 53 is connected between the downwardly cantedprotuberance 6ft projecting from the rocker element 51 and a rearwardlyprojecting protuberance 77 on an arm portion 78 of the interposer bail43. The spring coupling the rocker element and interposer bail is undercompression therebetween and exerts continual pressure against them.Therefore it acts as an over center toggle displaced above or below aline drawn through the respective pivot centers of the rocker elementand interposer bail, and, thus holds these two parts in their lastposition.

With reference to FIGS. 2, 3 and 4, the rocker element 51 is forciblytipped into one position or the other by the driver arm 52, which isurged forward under strong spring tension by the drive spring 72 toposition the spear pointed end thereof in one or the other of thescalloped cut-out camming portions 55 or 56 of the rocker element underwhich conditions the driver arm will be tipped on its pivot above orbelow the center of the rocker element. At the beginning of each printcycle or operation and prior to the movement of the lift shaft 24through the follower arm 31, the driver arm 52 is moved rearwardly outof the rocker element without displacing the setting or position of therocker element and interposer. As the driver arm is withdrawn from therocker element, which is shown as being tipped downwardly in FIG. 3, thearm will rock slightly clockwise about the pivot rod as the arm iswithdrawn from the lower cut-out camming portion 56 of the rockerelement, and is restored to a center position established by thecentering spring 61 and pivot rod, under which conditions the pointedend of the driver arm will be directed toward the pivot center and abovethe downwardly tipped nose 59 of the rocker element, as shown in FIG. 2.

The rearward movement of the driver arm is effected through the actionof the cam follower rocker arm 66, which is pivoted clockwise at thebeginning of the print cycle by the tensioned spring 68 and causes thedrive link 65 carrying the pivot rod 7 ii of the driver arm to shiftrearwardly and thereby to remove the tipped end of the latter from therocker element 51. During the subsequent rotation of the cam 6h, themotion of the rocker arm 66 is reversed, and it is pivotedcounterclockwise to cause the drive link 65 and the centered driver arm52 to shift forwardly until the point of the driver arm engages theupper cam surface 55 of the rocker element 51. As the driver arm isshifted forwardly, it switches or reverses the rocker element to theopposite position, carrying the interposer 43 and toggle spring 53therewith. The latter then holds the parts in their transferred positionof FIG. 4 in which the interposer tab 46 is positioned in the path ofthe shouldered cut-out portion 47 of the follower arm 31.

This action is illustrated diagrammatically in FIGS. 2, 3 and 4 in whichFIG. 3 illustrates the position of the interposer, rocker element anddriver arm at the completion of an upper ribbon field printing cycleduring which the lift arms received the minimum or lower lift by reasonof theinterposer having been positioned out of the path of the camfollower arm 31. The elongated slot 35 in the follower arm is seen toprovide a substantial amount of lost motion of the arm relative to thelift shaft 24 as the arm is swung counterclockwise by cam 40 andclockwise by the spring 38.

FIG. 2 illustrates the driver arm pulled rearward out of the upperscalloped cam portion 55 of the rocker element and nearly centered, thespear tipped end of the driver arm rising slightly above the downwardlytipped nose 59 of the rocker element to a position where it will engagethe upperside of the nose portion 59 and be directed into the upperscalloped cam portion 55 of the rocker element. Thus, as the driver armis driven forwardly, the upper cam portion will be presented thereto andwill be cammed thereby above center to rock the rocker elementcounterclockwise about its pivot to the position approximated in FIG. 4,switching the toggle spring below center with concomitant downward orclockwise rocking of the interposer into the path of the follower arm31. The retraction and repositioning of the driver arm was effected bythe rocker arm 66, which, as previously described, positions the drivelink 65 and hammer latch bail 64 prior to the movement of the lift shaft24 by the follower arm 31, but during the same printing cycle.

With the interposer tab 46 positioned to engage the notch 47 in thefollower arm 31, as shown in FIG. 4, the amount of lost motion of thefollower arm will be decreased, thus causing the short arm 30 toinitiate rotation of the lift shaft at a somewhat earlier time than thatobtained by the orientation shown in FIG. 3. Accordingly, the liftspindles will receive a greater lift and be positioned to a higher liftposition corresponding to the lower ribbon field. On the followingprinting cycle or operation, the previously mentioned ribbon advancingmechanism 28 advances the ribbon longitudinally a slight distance andthe alternator mechanism reverses the position of the rocker element,toggle spring and interposer back to the minimum lift controllingposition shown in FIG. 3 to cause printing through the advanced ribbonon the opposite printing field thereof, it being understood that theribbon is advanced on each printing cycle.

What is claimed is:

1. In a printing device including a ribbon having two printing fieldscorresponding to respective halves of the ribbon, the combination of, amounting frame, a ribbon supporting means mounted for movement on theframe, movable shifting means coupled to said ribbon support means toshift the latter from an inactive ribbon printing position to an activeribbon printing position in which one of said ribbon printing fields ispositioned for printing therethrough, interposer means mounted on saidframe and operable to be interposed in the path of movement of saidshifting means to alter the movement thereof and modify the shiftimparted to the ribbon supporting means to another active ribbonprinting position in which the other one of said ribbon printing fieldsis positioned for printing therethrough, a mechanically positionabletoggle mechanism mounted on said frame and coupled to said interposer toposition the latter in the path of said shifting means in one positionof the toggle mechanism and out of the path of the shifting means inanother position thereof, and driver means alternating the position ofthe toggle on successive printing operations of said printing device tocontrol the operation of said shifting means through said interposermeans for printing on alternate halves or fields of the ribbon onsuccessive printing operations of said printing device.

2. In a cyclically operable printing device including a ribbon havingtwo printing fields corresponding to the upper half and to the lowerhalf of the ribbon, the combination of a mounting frame, a ribbonsupporting means mounted for vertical movement on the frame, acyclically operable moveable lift means coupled to said ribbonsupporting means to lift the latter vertically from an inactive ribbonprinting position below an established printing line to an active ribbonprinting position in which one of said ribbon printing fields ispositioned at said line, interposer means mounted on said frame andoperable to be interposed in the path of movement of said lift means toalter the movement thereof and modify the vertical lift imparted to theribbon supporting means to another active ribbon printing position inwhich the other one of said ribbon printing fields is positioned at saidline, a rocker element pivotally mounted to the frame and rockable toeither of two positions, a compression spring coupling between saidrocker element and said interposer, and a cyclically Operable driver armdrivingly engaging the rocker element and alternating the position ofthe latter on successive printing cycles of said printing device tocontrol the operation of said lift means through said interposer meansfor printing on alternate halves of the ribbon on successive printingcycles of said printing device.

3. In a cyclically operable printing device including a ribbon havingtwo printing fields corresponding to the upper half and to the lowerhalf of the ribbon, the combination of a mounting frame, a ribbonsupporting means mounted for vertical movement on the frame, acyclically operable moveable lift means coupled to said ribbonsupporting means to lift the latter from an inactive ribbon printingposition below an established printing line to an active ribbon positionin which one of said ribbon printing fields is positioned at said line,interposer means pivotally mounted on said frame and operable to beinterposed in the path of movement of said lift means to alter themovement thereof and modify the lift imparted to the ribbon supportingmeans to another active ribbon position in which the other one of saidribbon printing fields is positioned at said line, a rocker elementpivotally mounted on said frame to either of two positions and spacedfrom the said interposer means, a compression spring of greater lengththan the spacing between said interposer means and rocker element andconnected therebetween to form an over-center toggle mechanismtherewith, and a cyclically operable driver arm drivingly engaging therocker element and alternating the position thereof on successiveprinting cycles of said printing device to control the operation of saidlift means through said interposer means for printing on alternatehalves of the ribbon on successive printing cycles of said printingdevice.

4. The combination in accordance with claim 3 above wherein said rockerelement includes a pair of camming surfaces located above and below thepivot center thereof and alternately cooperating with said driver arm.

5. In a printing device including a ribbon having two printing fieldscorresponding to respective halves of the ribbon, a mounting frame, aribbon supporting means mounted for movement on the frame, and movableshifting means coupled to said ribbon support means to shift the latterfrom an inactive ribbon printing position to an active ribbon printingposition in which one of said ribbon printing fields is positioned forprinting therethrough; a shift control mechanism controlling theshifting of the ribbon from said inactive ribbon printing position toalternate ones of two different ribbon printing positions on successiveprinting operations of said device, said shift control mechanismcomprising, interposer means mounted on said frame and operable to beinterposed into the path of movement of said shifting means for alteringthe movement thereof and modifying the shift imparted to the ribbonsupporting means to another active ribbon printing position in which theother one of said ribbon printing fields is positioned for printingtherethrough, a bistable element coupled to said interposer to positionthe latter in the path of said shifting means in one position of thebistable element and out of the path of the shifting means in anotherposition thereof, and driver means alternating the position of thebistable element on successive printing operations of said printingdevice to control the operation of said shifting means through saidinterposer means for printing on alternate halves or fields of theribbon on successive printing operations of said printing device.

6. In a device for printing a full line at a time, said device includinga shiftable support for a ribbon having at least two ribbon printingfields thereon, a shift mechanism operable on successive operations ofsaid printing device to shift the ribbon support from an inactive ribbonprinting position on one side of an established printing line todifferent ones of at least two active printing positions eachcorresponding to a different one of said printing fields of said ribbon,said shift mechanism including control means settable to at least twodifferent conditions each corresponding to a different one of saidribbon printing fields and controlling the extent of movement of saidshiftable ribbon support from said inactive ribbon printing position toany one of said active ribbon printing positions in accordance with thecondition of said settable control means, and setting means coupled tosaid settable control means and actuatable upon initiation of eachprinting operation to change the condition of said settable controlmeans from its previous condition to a successive one of its conditionson different similar printing operations of said printing device.

7. In a cyclically operated printing device employing a ribbon having aplurality of printing fields dividing the width of said ribbon into aplurality of parallel bands for printing on an established print line, ashiftable ribbon supporting mechanism, means for shifting saidmechanism, lost motion means between said shifting means. and saidribbon supporting mechanism enabling the shifting of said ribbonvariable amounts on successive cyclical operations of said printingdevice from an inactive printing position on one side of saidestablished print line to active printing positions superimposed uponsaid print line corresponding to diflerent ones of said ribbon printingfields, said shifting means including a cyclically actuated lost motionvarying means having plural stable states coupled to said lost motionmeans for variably shifting said ribbon amounts corresponding to each ofsaid active printing positions, and cyclical drive means coupled to saidlost motion varying means and altering its stable state once during eachcycle of said printing device.

References Cited in the file of this patent UNITED STATES PATENTS UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,147 703September BTHI964 Donald J. Smithbauer It is hereby certified that errorappears in the above-numbered patent requiring correction and that thesaid Letters Patent should read as corrected below,

Column 6, line 72, for "successive" read. diiferent line 73, for"different" read successive Signed and sealed this 20th day of April1965,

'(SEAL) 1\Ltest:

ERNEST W. SWIDER v EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. IN APRINTING DEVICE INCLUDING A RIBBON HAVING TWO PRINTING FIELDSCORRESPONDING TO RESPECTIVE HALVES OF THE RIBBON, THE COMBINATION OF, AMOUNTING FRAME, A RIBBON SUPPORTING MEANS MOUNTED FOR MOVEMENT ON THEFRAME, MOVABLE SHIFTING MEANS COUPLED TO SAID RIBBON SUPPORT MEANS TOSHIFT THE LATTER FROM AN INACTIVE RIBBON PRINTING POSITION TO AN ACTIVERIBBON PRINTING POSITION IN WHICH ONE OF SAID RIBBON PRINTING FIELDS ISPOSITIONED FOR PRINTING THERETHROUGH, INTERPOSER MEANS MOUNTED ON SAIDFRAME AND OPERABLE TO BE INTERPOSED IN THE PATH OF MOVEMENT OF SAIDSHIFTING MEANS TO ALTER THE MOVEMENT THEREOF AND MODIFY THE SHIFTIMPARTED TO THE RIBBON SUPPORTING MEANS TO ANOTHER ACTIVE RIBBONPRINTING POSTION IN WHICH THE OTHER ONE OF SAID RIBBON PRINTING FIELD ISPOSITIONED FOR PRINTING THERETHROUGH, A MECHANICALLY POSITIONABLE TOGGLEMECHANISM MOUNTED ON SAID FRAME AND COUPLED TO SAID INTERPOSER TOPOSITION THE LATTER IN THE PATH OF SAID SHIFTING MEANS IN ONE POSITIN OFTHE TOGGLE MECHANISM AND OUT OF THE PATH OF THE SHIFTING MEANS INANOTHER POSITION THEREOF, AND DRIVER MEANS ALTERNATING THE POSITION OFTHE TOGGLE ON SUCCESSIVE PRINTING OPERATIONS OF SAID PRINTING DEVICE TOCONTROL THE OPERATION OF SAID SHIFTING MEANS THROUGH SAID INTERPOSERMEANS FOR PRINTING ON ALTERNATE HAOVES OR FIELDS OF THE RIBBON ONSUCCESSIVE PRINTING OPERATIONS OF SAID PRINTING DEVICE.